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Full text of "The manufacture and properties of iron and steel"

314
METALLURGY OP IRON AND STEEL.
to the three-quarter inch tests, although the larger bar should give the better elongation. The inferiority is due to the removal of the best part of the piece in turning. This phenomenon is more marked in larger sizes, as shown by Table XVI-B, which gives the results on bars cut from forged bridge-pins.
TABLE XYI-B. Test-Pieces f-inch in Diameter, cut from Forged Rounds.
Size of Ingot, 18x20 inches.   Pennsylvania Steel Company, 1898.
T		l|	I 5.	1	'*	\    •
'   1-4		W Q<	o*	00	«•	ft
r«s		S™		^	•g	eT
"O ' We	Place from -which test -was taken.	"ft	s* '	*<&'		3" ct
£<!•}		1-3 .	•^•3 ^	"§§	S g	
,, 2 1|		S cM	33 §-3	M»	o f 0   M	3-g
Jg		3 °_ri	JS p<5	5 p,	t( S3 03 ft	M  O
		£>	H	H	c§	• H
'sin.	At a depth of 1 inch from outside. At a depth of 2 inches from outside. The central axis,	62720 68100 68100	82870 29170 81490	21.50 22.25 20.25	'  40.4 87.5 34.1	52.4 50.2 54.2
10 in.	At a depth of 1 inch from outside. At a depth of 2j& inches from outside. The central axis.	66070 62750 60900	87080 85670 82140	19.50 18.00 : 19.50	83.9 ' 82.T 23.8	56.1 56.8   . 62.8
Preliminary test of same heat from 6 in. ingot		63980 I   42250		26.25	41.7	66.1
•'   SEO.  XVIb.-1—Strips cut from  eye-bar flats.—Similar   differences will be found if test-pieces be cut from different parts of 'eye-bars, as illustrated by Table XVI-G.    These results display 'considerable uniformity in the higher strength of the bars from the large ingot, but the number of specimens is not sufficient to establish the fact.    Such a comparison is often invalidated by unknown factors, for if the test-bar be finished hot and the "flat" cold, the relation may be, reversed.   Table XVI-D shows the comparative results on nine heats of steel, and will illustrate how the preliminary test may differ from the finished bar in individual cases, while the average of the two is the same. ..•SEC.. XVIe.—Longitudinal   and    transverse   test-pieces   from ^Zaies.'-r-Differences may. also be found between strips cut lengthwise from'a plate and those cut crosswise.."Mr. A. E. Hunt states "that "in-^plates up to 30 inches wide there is, ordinarily, a difference of 10 per cent, in tensile strength, and up' to 20 or 25 per cent, in ductility in favor of pieces cut with the grain.   In wide